Medical Device and Treatment Method

ABSTRACT

A medical device has a rotatable drive shaft, a rotary body that includes a cutting edge for applying a cutting force to a stenosed site, and that is disposed on a distal side of the drive shaft so as to be rotated in conjunction with rotation of the drive shaft, a switching portion whose distal end is disposed at a position protruding from the cutting edge, and a holding portion that holds the switching portion so as to move the switching portion on the same plane as the cutting edge or to a position away from the stenosed site beyond the cutting edge in accordance with a pushing force, when the switching portion is pushed against the stenosed site.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/JP/2017/005377 filed on Feb. 14, 2017, which claims priority toJapanese Application No. 2016-026336 filed on Feb. 15, 2016, the entirecontents of both being incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a medical device and a treatment methodfor cutting an object which is present inside a biological lumen.

BACKGROUND ART

Treatment using a balloon catheter or an indwelling technique of a stenthas been used in the related art as a method of treating a stenosed siteformed inside a blood vessel such as a coronary artery. However, atherapeutic effect is less likely to be obtained over a long period oftime merely by using a balloon to widen a vascular lumen. It is knownthat stent indwelling causes a new stenosis. In addition, when acomplicated lesion develops, as in a case where a plaque of the stenosedsite is calcified and hardened, or in a case where the stenosed siteappears in a branched portion of the blood vessel, the therapeuticeffect cannot be sufficiently obtained merely by performing a treatmentusing a balloon catheter or stent.

On the other hand, as the treatment for extending patency of the bloodvessel or for contributing to an improved treatment outcome in thecomplicated lesion, there is known atherectomy for extracorporeallyremoving an object such as a plaque, a calcified lesion, or a thrombuswhich may cause the stenosis.

As a medical device for the atherectomy, for example, JP-T-2014-533147has proposed a medical device having a rotary body provided with acutting edge (blade surface) for applying cutting force to the stenosedsite disposed in a distal portion of an elongated catheter. In thetreatment using this medical device, work for pushing the cutting edgeagainst the stenosed site is carried out in a state where the rotarybody is rotated.

It is desirable that the medical device used for the treatment of thestenosed site formed inside a biological lumen is provided with variousfunctions which enable suitable treatment depending on a property, asize, a shape, or a forming site of the stenosed site. For example, inorder that the medical device is suitable for the particularcharacteristics of an object (stenosed site) serving as a treatmenttarget site, the medical device is provided with the ability toselectively switch the state of the cutting edge. In this manner, notonly it is possible to smoothly and quickly perform a medical procedure,but also it is possible to improve the therapeutic effect.

However, the medical device disclosed in JP-T-2014-533147 is notconfigured so that the distal portion (distally located end) having thecutting edge can be switched depending on the characteristics of theobject serving as the treatment target site. Therefore, the treatmentcannot be progressively performed while various functions of the medicaldevice are switched therebetween during the medical procedure. Forexample, in a case where the treatment is performed by switching variousfunctions therebetween, an operator has to temporarily remove themedical device out of a living body, replace the medical device itselfwith another medical device, or replace a member such as the rotarybody. Consequently, the medical procedure takes a longer time, therebyincreasing a burden on a patient.

The disclosure herein is made in view of the above-described problems,and aims to provide a medical device and a treatment method, in which amedical procedure can be smoothly and quickly performed and an improvedtherapeutic effect can be realized by enabling a state of a cutting edgeto be switched while inside a biological lumen.

SUMMARY

According to the disclosure herein, there is provided a medical devicefor cutting an object inside a biological lumen. The medical device hasa rotatable elongated member, a rotary body that includes a cutting edgefor applying a cutting force to the object, and that is disposed on adistal side of the elongated member so as to be rotated in conjunctionwith rotation of the elongated member, a switching portion whose distalend is disposed at a position protruding from the cutting edge, and aholding portion that holds the switching portion so as to move theswitching portion on the same plane as the cutting edge or to a positionaway from the object beyond the cutting edge in accordance with apushing force, when the switching portion is pushed against the object.

In addition, according to the disclosure here, there is provided atreatment method for cutting an object inside a biological lumen. Thetreatment method has a movement step of bringing a switching portioninto a state of protruding to a distal side of a rotary body including acutting edge for applying a cutting force to the object, and pushing theswitching portion against the object so as to move the switching portionon the same plane as the cutting edge or to a position away from theobject beyond the cutting edge, and a cutting step of causing thecutting edge to cut the object in a state where the switching portion ismoved.

According to the medical device in the disclosure here, a pushing forcefor pushing the switching portion against a predetermined object servingas a cutting target is adjustable. In this manner, a state of thecutting edge can be easily switched without taking out the medicaldevice from the biological lumen. In this manner, it is possible to savelabor needed to carry out work for switching the state of the cuttingedge, and it is possible to smoothly and quickly perform a medicalprocedure. In addition, the treatment can be progressively performedwhile the state of the cutting edge is appropriately switched dependingon the property of the object serving as the cutting target.Accordingly, it is possible to improve a therapeutic effect of themedical procedure using the medical device.

In the treatment method according to the disclosure herein, the state ofthe cutting edge is switched by adjusting the pushing force for pushingthe switching portion against the predetermined object serving as thecutting target. In addition, the treatment can be progressivelyperformed while the state of the cutting edge is appropriately switcheddepending on the property of the object serving as the cutting target.Therefore, according to the treatment method, the medical procedure canbe smoothly and quickly performed, and the therapeutic effect can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a medical device according to a first exemplaryembodiment of the disclosure.

FIG. 2A is an enlarged view of a rotary body included in the medicaldevice according to the first exemplary embodiment.

FIG. 2B is a cross-sectional view taken along an axial direction of therotary body included in the medical device according to the firstexemplary embodiment.

FIG. 3A is a front view of the rotary body when viewed in a direction ofan arrow 3A illustrated in FIG. 2.

FIG. 3B is an enlarged cross-sectional view of a portion surrounded by asingle-dot chain line 3B illustrated in FIG. 1.

FIG. 4A is a cross-sectional view schematically illustrating a treatmentexample using the medical device according to the first exemplaryembodiment.

FIG. 4B is a cross-sectional view schematically illustrating a treatmentexample using the medical device according to the first exemplaryembodiment.

FIG. 4C is a cross-sectional view schematically illustrating a treatmentexample using the medical device according to the first exemplaryembodiment.

FIG. 5A is a view for describing an operation of the medical deviceaccording to the first exemplary embodiment.

FIG. 5B is a view for describing an operation of the medical deviceaccording to the first exemplary embodiment.

FIG. 6 is a cross-sectional view illustrating a medical device accordingto Modification Example 1 of the first exemplary embodiment.

FIG. 7 is a cross-sectional view illustrating a medical device accordingto Modification Example 2 of the first exemplary embodiment.

FIG. 8 is a cross-sectional view illustrating a medical device accordingto Modification Example 3 of the first exemplary embodiment.

FIG. 9 is a cross-sectional view illustrating a medical device accordingto Modification Example 4 of the first exemplary embodiment.

FIG. 10 is a cross-sectional view illustrating a medical deviceaccording to Modification Example 5 of the first exemplary embodiment.

FIG. 11 is a cross-sectional view illustrating a medical deviceaccording to Modification Example 6 of the first exemplary embodiment.

FIG. 12 is a plan view illustrating a medical device according toModification Example 7 of the first exemplary embodiment.

FIG. 13A is an enlarged cross-sectional view illustrating aconfiguration of a proximal portion of the medical device according toModification Example 7.

FIG. 13B is an enlarged cross-sectional view illustrating aconfiguration of a distal portion of the medical device according toModification Example 7.

FIG. 14 is a plan view of a medical device according to a secondexemplary embodiment.

FIG. 15A is a partial cross-sectional view of a distal member includedin the medical device according to the second exemplary embodiment.

FIG. 15B is a bottom view of the distal member when viewed in adirection of an arrow 15B illustrated in FIG. 15A.

FIG. 16A is a perspective view illustrating a distal side of the medicaldevice according to the second exemplary embodiment.

FIG. 16B is a side view for describing a structure of an elongatedmember included in the medical device according to the second exemplaryembodiment.

FIG. 17A is a perspective view for describing an operation of a sidehole belonging to the distal member included in the medical deviceaccording to the second exemplary embodiment.

FIG. 17B is a perspective view for describing an operation of the sidehole belonging to the distal member included in the medical deviceaccording to the second exemplary embodiment.

FIG. 18A is a cross-sectional view schematically illustrating atreatment example using medical device according to the second exemplaryembodiment.

FIG. 18B is a cross-sectional view schematically illustrating atreatment example using medical device according to the second exemplaryembodiment.

FIG. 18C is a cross-sectional view schematically illustrating atreatment example using medical device according to the second exemplaryembodiment.

FIG. 19A is a view illustrating a distal member included in a medicaldevice according to Modification Example 1 of the second exemplaryembodiment.

FIG. 19B is a bottom view illustrating the distal member included in themedical device according to Modification Example 1 of the secondexemplary embodiment.

FIG. 20A is a view illustrating a distal member included in a medicaldevice according to Modification Example 2 of the second exemplaryembodiment.

FIG. 20B is a bottom view illustrating the distal member included in themedical device according to Modification Example 2 of the secondexemplary embodiment.

FIG. 20C is a cross-sectional view for describing an operation of thedistal member included in the medical device according to ModificationExample 2 of the second exemplary embodiment.

FIG. 21A is a view illustrating a distal member included in a medicaldevice according to Modification Example 3 of the second exemplaryembodiment.

FIG. 21B is a cross-sectional view for describing an operation of thedistal member included in the medical device according to ModificationExample 3 of the second exemplary embodiment.

FIG. 22 is a view illustrating a medical device according toModification Example 4 of the second exemplary embodiment.

FIG. 23 is a cross-sectional view for describing an operation of themedical device according to the second exemplary embodiment.

FIG. 24A is a view illustrating a distal member included in a medicaldevice according to Modification Example 5 of the second exemplaryembodiment.

FIG. 24B is a side view of the distal member included in the medicaldevice according to Modification Example 5 of the second exemplaryembodiment.

FIG. 25 is a view illustrating a medical device according toModification Example 6 of the second exemplary embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the disclosure will be describedwith reference to the drawings. Dimensional proportions in the drawingsare exaggerated and different from actual proportions for convenience ofdescription, in some cases.

First Embodiment

As illustrated in FIG. 4, a medical device 1 according to a firstexemplary embodiment is used in treatment for cutting a stenosed site(object) S or an occluded site formed in a blood vessel H which is abiological lumen. In the description herein, a side inserted into thebiological lumen in the medical device 1 will be referred to as a distalside (distally located side), and a side operated by a hand will bereferred to as a proximal side (proximally located side).

As illustrated in FIG. 1, the medical device 1 has an elongated tube(catheter) 80 which can be introduced into the biological lumen. Asillustrated in FIGS. 2A and 2B, a distal portion of the tube 80 has arotary body 20 including a cutting edge 21 for applying a cutting forceto the stenosed site S, a switching portion 30 (protector) whose distalend is disposed at a position protruding from the cutting edge 21, aholding portion 40 that holds the switching portion 30 at apredetermined position, a rotation receiving portion (corresponding to amain body portion) 50 disposed on a proximal side of the rotary body 20,and a cutting assistance portion 60 that assists cutting performed bythe cutting edge 21.

According to the first exemplary embodiment of the disclosure, theswitching portion 30 is configured to serve as a protector that preventsthe cutting edge 21 of the rotary body 20 from inadvertently coming intocontact with a biological tissue other than the stenosed site S which isa treatment target site.

The rotary body 20 internally has a hollow cylindrical shape. Thecutting edge 21 disposed on a distal end of the rotary body 20 isconfigured to include a sharp blade protruding toward the distal side.As illustrated in FIG. 2A, a side surface of the rotary body 20 has aside hole 23 through which an interior and an exterior of the rotarybody 20 communicate with each other.

For example, the rotary body 20 can be configured to include a knownmetal material, a resin material, or ceramics provided withbiocompatibility. For example, the metal material includes stainlesssteel, nickel titan (titanium alloy), tungsten, cobalt chromium, titan,and tungsten carbide. A surface of these metal materials is subjected tosurface treatment such as nitriding treatment. In this manner, it ispossible to use the metal material whose hardness at the surface isfurther improved over the base material. For example, the cutting edge21 may be configured to include a multiple layer structure in whichsimilar or dissimilar types of the metal are disposed in multiplelayers. For example, as the resin material, it is possible to use BS(acrylonitrile, butadiene, and styrene copolymer synthetic resin),polyethylene, polypropylene, nylon, PEEK, polycarbonate, acrylic,polyacetal, modified polyphenylene ether, acrylonitrile styrene, orthose which have improved strength by allowing these resin materials tocontain additives such as glass fibers.

The cutting edge 21 included in the rotary body 20 has a blade surface21 a cut in an uneven shape (saw-tooth shape). The blade surface 21 a isdisposed along a circumferential direction of the rotary body 20. In theblade surface 21 a included in the cutting edge 21, a shape, athickness, a length, and a material are not particularly limited, aslong as the cutting force can be applied to the stenosed site S.However, in a case where the blade surface 21 a has a saw-tooth shape asin the cutting edge 21, it is possible to finely crush the stenosed siteS. Therefore, the stenosed site S can be efficiently cut.

As illustrated in FIGS. 1 and 26, the rotary body 20 is disposed on thedistal side of a rotationally driven drive shaft (corresponding to anelongated member) 10. The rotary body 20 is rotated in conjunction withrotation of the drive shaft 10.

As illustrated in FIG. 2B, the drive shaft 10 has a core (core bar) 11and a reinforcement body 12 fixed to the core 11. For example, the core11 can be formed of a known metal material such as stainless steel. Thereinforcement body 12 can be formed of those which are obtained byspirally machining the known metal material such as the stainless steel.The reinforcement body 12 can be fixedly attached to an outer surface ofthe core 11 by using a known method such as bonding using an adhesiveand soldering.

As illustrated in FIG. 2B, a distal portion of the drive shaft 10 isfixed to an inner surface of the rotary body 20 via a plurality offixing portions b1. The distal portion of the drive shaft 10 is fixed tothe inner surface of the rotary body 20, and is disposed at a positionwhich is eccentric outward from a central axis Cl of the tube 80. Fixingat the fixing portion b1 can be performed by a method of bonding usingan adhesive, welding, or melting, for example.

As illustrated in FIG. 1, a proximal portion of the drive shaft 10 isconfigured to be connectable to an external drive apparatus 180 via apredetermined connector (not illustrated). The external drive apparatus180 includes a drive source configured to include a known electric motorwhich generates a rotational force for rotating the drive shaft 10. Ifthe rotational force generated by the external drive apparatus 180 isapplied to the drive shaft 10, the rotational force is transmitted fromthe proximal side to the distal side of the drive shaft 10, therebyrotating the rotary body 20 disposed in the distal portion of the driveshaft 10. If the rotary body 20 is rotated, the cutting edge 21 disposedin the distal end of the rotary body 20 can apply the cutting force tothe stenosed site S (refer to FIG. 4B).

The external drive apparatus 180 and an aspiration device 190 (to bedescribed later) can be controlled by a control unit (not illustrated),for example. For example, as the control unit, it is possible to usethose which are configured to include a known microcomputer having aCPU, a RAM, and a ROM. In addition, for example, the control unit may beinstalled in the external drive apparatus 180 or the aspiration device190, or may be incorporated in a device separate from the external driveapparatus 180 or the aspiration device 190. In this way, a controlsignal may be transmitted and received between the apparatus 180 and thedevice 190 in a wire or wireless manner.

As illustrated in FIG. 1, a hand operation unit 150 is disposed in theproximal portion of the tube 80. The hand operation unit 150 has a hub151, a connector portion 153 disposed in the hub 151, and a port 155disposed in the connector portion 153.

For example, the connector portion 153 can be configured to include aY-connector known in a medical field. A three-way plug for controllingcirculation of a fluid inside and outside the port 155 is disposed inthe port 155. For example, the port 155 can interlock with theaspiration device 190 via the tube 191 through which the fluid can becirculated. For example, the aspiration device 190 can be configured toinclude a known fluid aspiration pump which can generate negativepressure.

As illustrated in FIGS. 2B and 3B, the tube 80 includes a lumen 85extending in an extending direction of the tube 80. The lumen 85communicates with an interior of the hub 151. The drive shaft 10 isinserted into the lumen 85 of the tube 80. As illustrated in FIG. 2B, adistal portion of the drive shaft 10 is fixed to the rotary body 20. Inaddition, as illustrated in FIG. 1, the proximal side of the drive shaft10 is inserted into the lumen 85 and the hub 151 of the tube 80, and ispulled out from a proximal end port 152 of the hub 151. The proximalportion of the hub 151 has a valve body 157 for preventing the fluidfrom leaking out of the proximal end port 152.

In a case where the medical device 1 is delivered using a guide wirewhen the medical device 1 is introduced into the biological lumen, forexample, the guide wire can be inserted into the lumen 85 of the tube80. In addition, for example, the valve body 157 or the hub 151 canappropriately have a port for pulling out the guide wire from theproximal end of the medical device 1 without interfering with the driveshaft 10.

A structure or a material of the elongated member which transmits adrive force to the rotary body 20 is not particularly limited, as longas the rotational drive force can be transmitted from the proximal sideto the distal side of the elongated member (from the hand operation unit150 side to the rotary body 20 side). The elongated member may be anymember other than the drive shaft 10. For example, the elongated membercan be formed of a resin material. In a case where the elongated memberis formed of the resin material, for example, it is possible to use aresin-made tube configured to include a single layer or multiple layers,or those which are obtained by adding a reinforcement member such as ablade to the resin-made tube. In addition, for example, as the elongatedmember, it is also possible to use a metal pipe subjected to spiralmachining, a tightly wound coil spring, and those which are obtained bycoating these members with the resin-made tube.

As illustrated in FIGS. 2A and 2B, the protector (switching portion) 30has a hollow distal portion 31 which protrudes to the distal side beyondthe cutting edge 21 of the rotary body 20 in the state where an externalforce is not applied from the outside, a hollow proximal portion 33which is fixed to the proximal portion of the rotary body 20, and astretchable and deformable portion 35 which extends between the distalportion 31 and the proximal portion 33.

The stretchable and deformable portion 35 is configured to include ahollow coil spring which is stretchable along an extending direction(rightward-leftward direction in FIG. 2B) of the rotation receivingportion 50. The coil spring configuring the stretchable and deformableportion 35 has a gap 35 g disposed at a predetermined interval in theextending direction.

The stretchable and deformable portion 35 has a function to serve as theholding portion 40 for holding a position of the protector 30 andchanging the position of the protector 30. According to the firstexemplary embodiment, the protector 30 is configured to include thedistal portion of the holding portion 40 (stretchable and deformableportion 35). That is, the holding portion 40 and the protector 30 areintegrally formed from a single member.

For example, the protector 30 and the holding portion 40 (stretchableand deformable portion 35 can be configured to include a known metalmaterial or resin material provided with biocompatibility. For example,the holding portion 40 can also be configured to include a memberseparate from the protector 30. In addition, a material or a structureof the holding portion 40 is not particularly limited, as long as theholding portion 40 is stretchable and deformable. The holding portion 40can also be configured to include an elastically deformable member suchas a plate spring, resin rubber, sponge, and a spring obtained byspirally machining a metal pipe.

The proximal portion of the protector 30 is fixed to the inner surfaceof the rotary body 20 via a fixing portion b2. Fixing in the fixingportion b2 can be performed by a method of bonding using an adhesive,welding, or melting, for example.

The protector 30 prevents the cutting edge 21 from coming into contactwith the biological tissue other than the stenosed site S in a statewhere the protector 30 protrudes from the cutting edge 21. The holdingportion 40 holds the protector 30 (distal portion 31 of the protector30) so as to move the protector 30 on the same plane as the cutting edge21 or to a position away from the stenosed site S beyond the cuttingedge 21 in accordance with the pushing force, when the protector 30 ispushed against the stenosed site S (refer to FIG. 5A). If the protector30 moves on the same plane as the cutting edge 21 or to the positionaway from the stenosed site S beyond the cutting edge 21, the cuttingedge 21 is in brought into a state of being in contact with the stenosedsite S. Accordingly, the cutting force can be applied to the stenosedsite S. That is, the protector 30 has a function to reversibly switchthe cutting edge 21 between a first orientation (state) which canprevent the cutting edge 21 from coming into contact with the biologicaltissue and a second orientation (state) which enables the cutting edge21 to cut the stenosed site S.

The above description of “switching” does not only mean switchingbetween the state of enabling the cutting edge 21 to cut the stenosedsite S and the state of preventing the cutting edge 21 from coming intocontact with the biological tissue, but also means switching betweeninfluences of cutting edge 21 on the biological tissue and the stenosedsite S. For example, as will be described in modification examples (tobe described later), switching the state of enabling the cutting edge 21itself to cut the stenosed site S and the state of enabling a memberother than the cutting edge 21 to cut the stenosed site S is alsoincluded in the above description of “switching”.

The protector 30 can be configured to protrude 0.5 mm from the cuttingedge 21, for example, in a state where no load is applied from theoutside. In addition, in a case where the protector 30 is moved to aposition away from the stenosed site S beyond the cutting edge 21 bybeing pushed against the stenosed site S, for example, the protector 30can be configured to be located 0.3 mm away from the cutting edge 21.These dimensions are only examples, and the exemplary embodiment is notparticularly limited to these dimensions.

As illustrated in FIGS. 2A and 2B, the rotation receiving portion 50 hasa distal opening portion 51, a proximal opening portion 53, a lumen 55linked between the distal opening portion 51 and the proximal openingportion 53, and a side hole 56 disposed on the side surface.

An inner surface on the distal side of the rotation receiving portion 50is provided with a stepped portion whose tube wall thickness is thinnerthan the other portions. The proximal portion of the rotary body 20 isinserted into the stepped portion.

An arrangement or a fixing structure of the rotary body 20 and the tube80 inside the rotation receiving portion 50 can be appropriatelychanged. For example, the stepped portion may not be disposed in therotation receiving portion 50. The tube 80 may be inserted into therotation receiving portion 50, and the tube 80 may narrow the innerdiameter of the rotation receiving portion 50 so as to provide thestepped portion. In this manner, the rotary body 20 may be inserted intothe stepped portion.

The interior of the rotary body 20 and the lumen 55 of the rotationreceiving portion 50 communicate with each other. If the rotary body 20is rotated and the side hole 56 of the rotation receiving portion 50 isdisposed at a position overlapping the side hole 23 of the rotary body20, a portion of the gap 35 g disposed in the stretchable and deformableportion 35 is exposed outward (state illustrated in FIG. 2A).

When the rotary body 20 is rotated, the proximal portion of the rotarybody 20 is supported by the inner surface of the rotation receivingportion 50. The proximal portion of the rotary body 20 is thus supportedby the rotation receiving portion 50. In this manner, the rotary shaftof the rotary body 20 is stabilized. Accordingly, the rotary body 20 issmoothly rotated. The rotation receiving portion 50 is not fixed to therotary body 20. Accordingly, the rotation receiving portion 50 is notrotated when the rotary body 20 is rotated.

The distal end of the tube 80 is inserted into the proximal side of therotation receiving portion 50. The distal end (distal end of the outerlayer 82) of the tube 80 is fixed to the inner surface of the rotationreceiving portion 50. The tube 80 and the rotary body 20 can be fixed toeach other by a method of bonding using an adhesive, welding, ormelting, for example.

As illustrated in FIG. 3B, the tube 80 has a tube main body 81 and anouter layer 82 for covering the tube main body 81.

At least one first slit 81 a is disposed on the distal side of the tubemain body 81, and at least one second slit 81 b is disposed on theproximal side of the first slit 81 a. The first slit 81 a has a smallerslit interval than the second slit 81 b. The first slit 81 a is disposedon the distal side of the tube main body 81. Accordingly, the distalside can be curved with a relatively large curvature. On the other hand,the second slit 81 b is disposed on the proximal side of the tube mainbody 81. Accordingly, the proximal side can be curved with a relativelysmall curvature. For example, the tube main body 81 can be configured toinclude a known metal material or a hard resin material.

In the outer layer 82, the material of the tube 80 is allowed to be moreflexible. Furthermore, when the biological tissue and the tube 80 comeinto contact with each other, the outer layer 82 protects the biologicaltissue. In addition, the outer layer 82 prevents a debris D flowing intothe tube 80 from being discharged from the tube 80. For example, as theouter layer 82, it is possible to use a hollow tube configured toinclude a known resin material such as polyethylene, polypropylene, andpolyamide.

As illustrated in FIG. 2B, the cutting assistance portion 60 is disposedso that the distal end protrudes from the distal end of the protector 30and the proximal end is fixed to the proximal portion of the holdingportion 40. The proximal end of the cutting assistance portion 60 isfixed to the inner surface of the holding portion 40 via the fixingportion b3. Fixing at the fixing portion b3 can be performed by a methodof bonding using an adhesive, welding, or melting, for example. Theproximal end of the cutting assistance portion 60 is fixed at a positionon the proximal side beyond the stretchable and deformable portion 35 ofthe protector 30. Accordingly, when the cutting assistance portion 60 ispushed against the stenosed site S, it is possible to prevent anexcessive force from being applied to the stretchable and deformableportion 35. In this manner, it is possible to preferably prevent damageto the stretchable and deformable portion 35.

The cutting assistance portion 60 has a hollow shape. In addition, asillustrated in FIG. 3A, in a front view, the cutting assistance portion60 has a substantially U-shape which has a cutout portion formed in aportion in the circumferential direction. In the medical device 1according to the first exemplary embodiment, the cutting assistanceportion 60 is disposed so as to protrude from the distal portion 31 ofthe protector 30 regardless of the stretchable deformation (deformationin the axial direction) of the holding portion 40. Therefore, in orderto prevent the biological tissue from being inadvertently damaged by thecutting assistance portion 60, it is preferable to configure the cuttingassistance portion 60 so as to have a shape which can minimize thecutting force, compared to the cutting edge 21 of the rotary body 20including the blade surface 21 a having a saw-tooth shape.

A shape or a size of the cutting assistance portion 60, and a positionalrelationship between the cutting assistance portion 60 and the protector30 are not limited to the illustrated examples, and can be appropriatelychanged. For example, the cutting assistance portion having a solidstructure can be used, or the shape or the arrangement can be changed soas to be capable of preventing interference with the guide wire insertedinto the rotary body 20.

As illustrated in FIG. 2B, the cutting assistance portion 60 isindirectly fixed to the rotary body 20 via the proximal portion(proximal portion 33 of the protector 30) of the holding portion 40. Ifthe rotary body 20 is rotated, the holding portion 40 is rotated inconjunction with the rotation of the rotary body 20, and the cuttingassistance portion 60 is also rotated. When the cutting is performed,prior to the cutting edge 21, the cutting assistance portion 60 entersthe inside of the stenosed site S serving as the cutting target, andforms a cutout portion inside the stenosed site S. If the cutting edge21 of the rotary body 20 is pushed against the stenosed site S in astate where the cutout portion is formed, the stenosed site S can bemore easily cut, compared to a case where no cutout portion is formed.In addition, if the cutting edge 21 is pushed against the stenosed siteS in a state where the cutting assistance portion 60 enters the insideof the stenosed site S, the cutting assistance portion 60 supports therotary body 20 with respect to the stenosed site S. Accordingly,misalignment of the rotary shaft of the rotary body 20 is suppressed. Inthis manner, particularly in a case where the stenosed site S serving asthe treatment target site is a calcified lesion, the cutting can beefficiently performed using the cutting edge 21 of the rotary body 20.

Next, referring to FIGS. 4A to 4C, 5A, and 5B, a treatment method usingthe medical device 1 will be described. Herein, a method of cutting thestenosed site S formed in the blood vessel H will be described as anexample.

First, as illustrated in FIG. 4A, a guiding sheath 170 is introduced tothe vicinity of the stenosed site S. The guiding sheath 170 can bedelivered to the vicinity of the stenosed site S along a guide wire (notillustrated) introduced before the guiding sheath 170 is introduced.When the guiding sheath 170 is delivered, using the guide wire may beappropriately omitted.

Next, the medical device 1 is delivered to the vicinity of the stenosedsite S via the guiding sheath 170. In this case, the medical device 1can be delivered along the guide wire by inserting the guide wire intothe hub 151, the tube 80, the protector 30, and the holding portion 40.While the medical device 1 is delivered to the vicinity of the stenosedsite S, the medical device 1 is in a state where the external force isnot applied to the protector 30 and the holding portion 40. Accordingly,as illustrated in FIGS. 2A and 2B, the protector 30 is in a state ofprotruding from the cutting edge 21 of the rotary body 20. Therefore, itis possible to prevent the cutting edge 21 from inadvertently cominginto contact with a normal biological tissue of the vascular wall.

Next, as illustrated in FIG. 4B, while the rotary body 20 is rotated asindicated by an arrow r, the medical device 1 is pushed against thestenosed site S from the distal side. As illustrated in FIG. 5A, if apushing force f1 is added toward the proximal side by pushing theprotector 30 against the stenosed site S, the pushing force f1 istransmitted to the holding portion 40 holding the protector 30, and theholding portion 40 is contracted to the proximal side. If the holdingportion 40 is contracted, the protector 30 moves so as to be drawn intothe rotary body 20. Then, the distal end of the protector 30 moves onthe same plane as the cutting edge 21 or to the position away from thestenosed site S beyond the cutting edge 21. If the cutting edge 21 isbrought into a state of protruding from the distal side beyond theprotector 30, the cutting force can be applied from the cutting edge 21to the stenosed site S. Accordingly, a stenosed substance (for example,a plaque or a thrombus) of the stenosed site S can be cut off.

When the stenosed substance of the stenosed site S is cut by rotatingthe cutting edge 21, for example, the aspiration device 190 illustratedin FIG. 1 is operated. In this manner, the cut stenosed substance(debris) D can be aspirated into the rotary body 20. The debris D flowsinto the rotary body 20 by way of the distal opening portion of therotary body 20, and flows toward the proximal side by way of the tube 80which communicates with the proximal side of the rotary body 20. In thismanner, the debris D is collected by the aspiration device 190. In thiscase, an aspirating force of aspirating the debris D into the rotarybody 20 is increased by a convection flow induced by the rotation of therotary body 20. Accordingly, the debris D smoothly moves toward theinterior of the rotary body 20.

In addition, as illustrated in FIG. 5B, the debris D is aspirated intothe protector 30 by way of the side hole 56 disposed in the rotationreceiving portion 50, the side hole 23 disposed in the rotary body 20,and the gap 35 g disposed in the stretchable and deformable portion 35.The debris D is aspirated from the distal side of the rotary body 20 andthe side surface side of the protector 30. In this manner, the debris Dcan be efficiently collected, and it is possible to prevent the debris Das a cutting scrap from being accumulated around the rotary body 20.Therefore, it is possible to prevent the debris D from sticking to thecutting edge 21 of the rotary body 20, and it is possible to increasethe cutting force applied to the stenosed site S by the cutting edge 21.

When the stenosed site S is cut by the rotary body 20, while the cuttingassistance portion 60 is rotated in conjunction with the rotary body 20,the cutting force is applied to the stenosed site S on the distal sidebeyond the rotary body 20. In the stenosed site S, a portion to whichthe cutting force is applied by the rotary body 20 is in a state ofbeing cut in advance by the cutting assistance portion 60. Therefore, ina portion with which the cutting edge 21 of the rotary body 20 comesinto contact, the stenosed site S is brittle. Accordingly, it ispossible to prevent the rotation of the rotary body 20 from beinghindered due to the contact, and the cutting can be smoothly andprogressively performed by the rotary body 20. For example, even in acase where the stenosed site S is formed to be relatively rigid, thecutting edge 21 of the rotary body 20 is brought into contact with aportion in which auxiliary cutting is performed by the cuttingassistance portion 60. Accordingly, the cutting force can besufficiently applied to the stenosed site S.

As illustrated in FIG. 5A, when the drive shaft 10 is rotated, a rotaryshaft thereof is displaced to a position eccentric from the central axisCl of the tube 80. The reason that the rotary shaft is displaced to theeccentric position in this way is that the drive shaft 10 is fixed tothe inner surface of the rotary body 20 located on the outer peripherybeyond from the central axis Cl of the tube 80. A rotational orbit ofthe drive shaft 10 is an elliptical orbit indicated by an arrow r1.While the drive shaft 10 is rotated by drawing the elliptical orbit, thedrive shaft 10 applies a shear force to the debris D flowing into therotary body 20 and into the tube 80. The debris D is finely crushed bythe applied shear force. Since the debris D is crushed, it is possibleto prevent clogging of the debris D inside the rotary body 20 and insidethe tube 80. Then, it is possible to smoothly move the debris D to theproximal side of the tube 80 by preventing the aspirating force frombeing weakened due to the clogging of the debris D. The drive shaft 10is inserted along the extending direction of the lumen 85 of the tube80. Accordingly, the shear force can be applied to the debris D atvarious locations in the extension direction of the tube 80. Therefore,the debris D is more finely crushed as the debris D flows to theproximal side. Accordingly, even in a case where a relatively largeamount of the debris D is aspirated into the tube 80 within a shortperiod of time, it is possible to preferably prevent clogging by thedebris D.

As illustrated in FIG. 4C, the medical device 1 is moved to the distalside so that the cutting edge 21 of the rotary body 20 is pushed againstthe stenosed site S. Through this work, the stenosed site S can be cutalong the extending direction. After it is confirmed that the cuttingtreatment is completely performed on the stenosed site S, the medicaldevice 1 is appropriately removed from the living body. It is alsopossible to subsequently perform the cutting treatment on the otherstenosed site S.

As described above, the medical device 1 according to the firstexemplary embodiment includes the rotatable drive shaft 10 and a cuttingedge 21 for applying the cutting force to the stenosed site S, and hasthe rotary body 20 disposed on the distal side of the drive shaft 10 androtated in conjunction with the drive shaft 10, the switching portion 30whose distal end is disposed at the position protruding from the cuttingedge 21, and the holding portion 40 that holds the switching portion 30so as to move the switching portion 30 on the same plane as the cuttingedge 21 or to the position away from the stenosed site S beyond thecutting edge 21 in accordance with the pushing force, when the switchingportion 30 is pushed against the stenosed site S.

According to the medical device 1 configured as described above, thepushing force for pushing the switching portion 30 against the stenosedsite S serving as the cutting target is adjusted. In this manner, theproperty of the cutting edge 21 can be easily switched without takingout the medical device 1 from the blood vessel H. In this manner, it ispossible to save labor needed to carry out work for switching the stateof the cutting edge 21, and it is possible to smoothly and quicklyperform the medical procedure. In addition, the treatment can beprogressively performed while the state of the cutting edge 21 isappropriately switched depending on the property of the stenosed site S.Accordingly, it is possible to improve the therapeutic effect of themedical procedure using the medical device 1.

In addition, in a case where the switching portion 30 is configured toserve as the protector 30 for protecting the cutting edge 21, thepushing force for pushing the protector 30 against the stenosed site Sserving as the cutting target is adjusted. In this manner, it ispossible to reversibly switch between the state where the protector 30protrudes from the cutting edge 21 of the rotary body 20 and the statewhere the protector 30 moves on the same plane as the cutting edge 21 orto the position away from the stenosed site S beyond the cutting edge21. When the protector 30 is brought into a state of protruding from thecutting edge 21, it is possible to prevent the cutting edge 21 frominadvertently coming into contact with the biological tissue (forexample, a normal biological tissue) other than the stenosed site.Accordingly, when performing the treatment, an operator does not have topay extra attention to the treatment. In this manner, the quicktreatment can be realized, and the burden felt by a patient due to thetreatment can be reduced.

The rotation receiving portion 50 having the lumen 55 for communicatingwith the interior of the rotary body 20 is disposed in the proximal endof the rotary body 20. The holding portion 40 is configured to bestretchable and deformable along the extending direction of the rotationreceiving portion 50. Therefore, the holding portion 40 is stretched anddeformed in conjunction with the operation for pushing the protector 30against the stenosed site S and the operation for releasing the pushedstate. In this manner, the protector 30 can be reversibly moved to theposition protruding from the cutting edge 21, and on the same plane asthe cutting edge 21 or the position away from the stenosed site S beyondthe cutting edge 21.

In addition, the rotation receiving portion 50 has a tubular shapeincluding the distal opening portion 51, the proximal opening portion53, and the lumen 55 linked to the distal opening portion 51 and theproximal opening portion 53. At least a portion of the holding portion40 is inserted into the rotation receiving portion 50. The protector 30is configured to be movable in the inward-outward direction (axialdirection) of the rotation receiving portion 50 by the stretchabledeformation of the holding portion 40. Therefore, the protector 30 canbe moved into and out of the rotation receiving portion 50 inconjunction with the stretchable deformation of the holding portion 40.The protruding amount of the protector 30 protruding from the rotationreceiving portion 50 is thus adjustable. In this manner, it is possibleto switch between the state where the cutting can be performed by thecutting edge 21 of the rotary body 20 and the state where the cuttingperformed by the cutting edge 21 is limited.

In addition, the holding portion 40 is configured to include a hollowspring 35, and the protector 30 is integrally disposed in the distalportion of the holding portion 40. Therefore, the holding portion 40 canbe easily moved by elastically deforming the spring 35. In addition, theprotector 30 and the holding portion 40 are disposed integrally witheach other. In this manner, it is possible to minimize an increase inthe number of components. Accordingly, it is possible to reduce themanufacturing cost.

In addition, the side surface of the rotation receiving portion 50 hasthe side hole 56 through which the interior of the holding portion 40and the exterior of the rotation receiving portion 50 communicate witheach other. Therefore, the debris D generated when the stenosed site Sis cut can be efficiently collected into the holding portion 40.Accordingly, it is possible to prevent the cutting force from beingweakened due to the generated debris D.

In addition, the medical device 1 further includes the cuttingassistance portion 60 disposed in the rotary body 20 so as to assist thecutting performed by the cutting edge 21. The distal side of the cuttingassistance portion 60 is disposed so as to protrude from the distal endof the protector 30. The proximal side of the cutting assistance portion60 is fixed to the proximal side of the holding portion 40. Therefore,the cutting efficiency of the stenosed site S can be improved by thecutting assistance portion 60.

In addition, the cutting edge 21 included in the rotary body 20 has theblade surface 21 a which is cut in an uneven shape. Accordingly, thestenosed site S can be finely crushed. Even in a case where the stenosedsite S serving as the treatment target site is a calcified lesion, thestenosed site S can be efficiently cut.

The treatment method according to the first exemplary embodimentincludes bringing the switching portion 30 into a state of protruding tothe distal side of the rotary body 20 including the cutting edge 21 forapplying the cutting force to the stenosed site S and pushing theswitching portion 30 against the stenosed site S so as to move theswitching portion 30 on the same plane as the cutting edge 21 or to theposition away from the stenosed site S beyond the cutting edge 21, andthe step of causing the cutting edge 21 to cut the stenosed site S in astate where the switching portion 30 is moved.

According to the treatment method described above, the state of thecutting edge 21 is switched by adjusting the pushing force for pushingthe switching portion 30 against the stenosed site S serving as thecutting target. The treatment can be progressively performed while thestate of the cutting edge 21 is appropriately switched depending on theproperty or characteristics of the stenosed site S. Therefore, accordingto this method, the medical procedure can be smoothly and quicklyperformed, and the therapeutic effect can be improved.

In addition, the switching portion 30 is configured to include theprotector 30, and the protector 30 is brought into a state of protrudingfrom the cutting edge 21. In this manner, it is possible to prevent thecutting edge 21 from inadvertently coming into contact with thebiological tissue other than the stenosed site S. Then, the protector 30is pushed against the stenosed site S so as to move the cutting edge 21on the same plane as the cutting edge 21 or to the position away fromthe object beyond the cutting edge 21. In this manner, the treatment canbe performed using the cutting edge 21. According to this method, theoperator does not have to pay extra attention to the treatment when thetreatment is performed. Accordingly, the quick treatment can berealized, and the burden felt by the patient due to the treatment can bereduced.

In addition, the step of moving the protector 30 is performed in such away that the holding portion 40 for holding the protector 30 iscontracted and deformed along the extending direction of the rotationreceiving portion 50 including the lumen 55 communicating with theinterior of the rotary body 20. Therefore, the holding portion 40 can bestretched in conjunction with the operation for pushing the protector 30against the stenosed site S and the operation for releasing the pushedstate, and furthermore, the protector 30 can be reversibly moved.

In addition, at least a portion of the holding portion 40 is disposedinside the rotation receiving portion 50, and the protector 30 isconfigured to be movable in the inward-outward direction of the rotationreceiving portion 50 by the stretchable deformation of the holdingportion 40. Therefore, the protector 30 can be moved into and out of therotation receiving portion 50 in conjunction with the stretchabledeformation of the holding portion 40. The protruding amount of theprotector 30 protruding from the rotation receiving portion 50 isadjustable. In this manner, it is possible to switch between the statewhere the cutting can be performed by the cutting edge 21 and the statewhere the cutting performed by the cutting edge 21 is limited.

In addition, the holding portion 40 is configured to include the hollowspring 35, and the protector 30 is integrally disposed in the distalportion of the holding portion 40. Therefore, the holding portion 40 canbe easily moved by elastically deforming the spring 35. In addition, theprotector 30 and the holding portion 40 are disposed integrally witheach other. In this manner, it is possible to minimize an increase inthe number of components. Accordingly, it is possible to reduce themanufacturing cost.

The above-described treatment method further has the step of introducingthe cut debris D into the rotation receiving portion 50 and into theholding portion 40 via the side hole 56 disposed on the side surface ofthe rotation receiving portion 50. Therefore, the debris D generatedwhen the stenosed site S is cut can be efficiently collected into theholding portion 40. In this manner, it is possible to prevent thecutting force from being weakened due to the generated debris D.

In addition, the cutting step includes the step of cutting the stenosedsite S while the cutting edge 21 is assisted by the cutting assistanceportion 60 disposed in the rotary body 20. Therefore, the cuttingassistance portion 60 can assist the cutting of the stenosed site S, andthe cutting edge 21 of the rotary body 20 can improve the cuttingefficiency. In particular, in a case where the stenosed site S isprogressively calcified and becomes harder, a cutting assistancefunction of the cutting assistance portion 60 is satisfactorilyfulfilled.

Next, a medical device according to Modification Example 1 of the firstexemplary embodiment will be described.

As illustrated in FIG. 6, in this modification example, the protector130 is disposed on the outer surface of the rotary body 20. Theprotector 130 is configured to include an elastic member having asubstantially tubular shape. For example, as the elastic member, it ispossible to use resin rubber, sponge, or elastically deformable metal.

The elastic member configuring the protector 130 also has a function toserve as the holding portion 40 for holding the protector 130.

For example, the proximal portion of the protector 130 can be fixed tothe outer surface of the proximal portion of the rotation receivingportion 50. Fixing can be performed by a method of bonding using anadhesive, welding, or melting, for example. The protector 130 is notfixed to the rotary body 20. Accordingly, the rotary body 20 is notrotated in conjunction with the rotation of the rotary body 20.

The thickness of a portion of the protector 130 in the circumferentialdirection can be further thickened than other portions. In thismodification example, for example, a portion 130 b on a lower portionside (bottom surface side) in the circumferential direction is thickerthan a portion 130 a on an upper portion side. Compared to the thinportion 130 a, the cutting force of the cutting edge 21 is less likelyto act on the thick portion 130 b of the protector 130, when thestenosed site S is cut, thereby suppressing the cutting. Therefore, thecutting is preferentially performed on the thin portion 130 a side ofthe protector 130. Accordingly, a forward movement direction of therotary body 20 is guided inward of the stenosed site S (outward whenviewed from the center of the blood vessel). As a result, the cuttingedge 21 of the rotary body 20 can be prevented from coming into contactwith a portion (portion located on the lower side in FIGS. 4A to 4C) ofthe vascular wall located on a side facing the stenosed site S.Accordingly, it is possible to further improve the safety of the medicalprocedure.

In the protector 130, for example, if the thick portion 130 b isdisposed in at least a portion located on the vertically downwarddirection side when viewed from the central axis of the protector 130,on an axially orthogonal cross-section of the protector 130, a functionof guiding the moving direction of the above-described rotary body 20can be fulfilled. Therefore, determining which range is suitable for thearrangement is not particularly limited.

Next, a medical device according to Modification Example 2 of the firstexemplary embodiment will be described.

As illustrated in FIG. 7, in this modification example, the protector230 is configured to include the elastic member which can be externallymounted on the outer surface of the rotation receiving portion 50. Forexample, as the elastic member, it is possible to use resin rubber,sponge, or elastically deformable metal.

The protector 230 internally has a hollow shape, and is externallymounted so as to cover the proximal portion of the rotation receivingportion 50. The protector 230 has an inclined cutout portion whichexternally exposes a portion of the side hole 56 of the rotationreceiving portion 50, in a state where the protector 230 is externallymounted on the rotation receiving portion 50. The bottom portion 230 blocated in the distal end of the protector 230 extends to the distalside. The bottom portion 230 b has a function to prevent the cuttingedge 21 of the rotary body 20 from coming into contact with thebiological tissue other than the stenosed site S. The proximal end ofthe protector 230 has a function to serve as the holding portion 40which holds the protector 230 with respect to the rotation receivingportion 50.

The protector 230 is not fixed to the rotary body 20. Accordingly, theprotector 230 is not rotated in conjunction with the rotation of therotary body 20.

In the distal portion of the protector 230, only the bottom portion 230b side protrudes. Therefore, when the stenosed site S is cut, the bottomportion 230 b comes into contact with the stenosed site S. When thecutting is performed by the cutting edge 21 of the rotary body 20,similar to Modification Example 1 described above, the cutting isthereby suppressed on the bottom portion 230 b side. Accordingly, theforward movement direction of the rotary body 20 is guided inward of thestenosed site S (outward when viewed from the center of the bloodvessel). Therefore, the cutting edge 21 of the rotary body 20 can beprevented from coming into contact with the portion of the vascular walllocated on the side facing the stenosed site S. Accordingly, it ispossible to further improve the safety of the medical procedure.

As described above with reference to Modification Examples 1 and 2, thestructure of the protector and the holding portion can prevent thecutting edge disposed on the distal end of the rotary body frominadvertently coming into contact with a site other than the stenosedsite (object). A specific configuration is not particularly limited, aslong as the protector and the holding portion are pushed against theobject so as to be switched to a state where the cutting edge can comeinto contact with the object.

Next, a medical device according to Modification Example 3 of the firstexemplary embodiment will be described.

As illustrated in FIG. 8, in this modification example, a cutting edge121 of a rotary body 120 is provided with a tapered blade surface 121 awhose thickness is thinned toward the distal side of the rotary body120.

For example, the blade surface 121 a can have a shape the same as thatof a trepanned blade surface (blade surface having a tapered shapetoward the distal side and having the smooth distal surface) used for abiopsy device in the medical field. The cutting edge 121 includes theblade surface 121 a. In this manner, when the stenosed site S is cut,the blade surface 121 a is pushed against the stenosed site S whilebeing rotated. Accordingly, the blade surface 121 a can smoothly enterthe inside of the stenosed site S, and the cutting force can be appliedso as to cut off the stenosed site S. In this manner, even in a casewhere the stenosed site S is a soft tissue, the cutting of the stenosedsite S can be efficiently performed.

Next, a medical device according to Modification Example 4 of the firstexemplary embodiment will be described.

As illustrated in FIG. 9, in this modification example, the distal endof the switching portion 330 is provided with a cutting portion 331which applies the cutting force to the stenosed site S. The cuttingportion 331 is disposed in the switching portion 330. Accordingly, thestenosed site S can be cut by pushing the switching portion 330 againstthe stenosed site S.

For example, in a state where the switching portion 330 is pushedagainst the stenosed site S by using a slightly weaker pushing force,the cutting can be performed using the cutting portion 331. The pushingforce applied to the stenosed site S is then increased so that theswitching portion 330 moves rearward to the proximal side. In thismanner, the cutting can be performed using the cutting edge 21 of therotary body 20. That is, in this modification example, the switchingportion 330 has a function to switch between the state where the cuttingis performed using the cutting edge 21 of the rotary body 20 and thestate where the cutting is performed using the cutting portion 331 ofthe switching portion 330.

For example, a blade surface 331 a of the cutting portion 331 of theswitching portion 330 can be configured to include a trepanned bladesurface. In addition, in a case where the blade surface 331 a isconfigured to include the trepanned blade surface, for example, theblade surface 21 a of the cutting edge 21 of the rotary body 20 can beconfigured to include the blade surface having a saw-tooth shape. In acase where the shape of the respective blade surfaces 21 a and 331 a isconfigured in this way, the treatment for cutting off the stenosed siteS having a soft tissue by using the blade surface 331 a included in theswitching portion 330 and the treatment for finely crushing thecalcified lesion by using the blade surface 21 a included in the rotarybody 20 can be realized using a single medical device. Furthermore, theblade surface 331 a of the switching portion 330 which first applies thecutting force to the stenosed site S is configured to include thetrepanned blade surface. Accordingly, after the blade surface 331 aforms a cutout portion in the stenosed site S, the blade surface 21 aconfigured to have the saw-tooth shape can enter the cutout portion. Theblade surface 21 a easily enters the inside of the stenosed site S.Accordingly, the stenosed site S can be more finely crushed by the bladesurface 21 a, and the therapeutic effect can be improved. Furthermore,the blade surface 331 a of the switching portion 330 located on thedistal side beyond the rotary body 20 is configured to include thesmooth blade surface such as the trepanned blade surface. Accordingly,the safety for the vascular wall is improved.

The shape of the blade surface 21 a included in the rotary body 20 andthe shape of the blade surface 331 a included in the switching portion330 are not limited to the illustrated examples, and can beappropriately changed. For example, both the blade surfaces 21 a and 331a can be configured to include the blade surface having the saw-toothshape or the trepanned blade surface. Alternatively, the blade surface331 a included in the switching portion 330 can be configured to includethe blade surface having the saw-tooth shape, and the blade surface 21 aincluded in the rotary body 20 can be configured to include thetrepanned blade surface.

Next, a medical device according to Modification Example 5 of the firstexemplary embodiment will be described.

As illustrated in FIG. 10, this modification example employs anarrangement in which the position of the distal end of the cuttingassistance portion 60 is located on the proximal side beyond theswitching portion 30, in a state where the external force is not appliedto the switching portion 30. Even in this arrangement, the pushing forcefor pushing the switching portion 30 against the stenosed site S isadjusted. In this manner, the cutting assistance portion 60 can protrudefrom the distal end of the switching portion 30, and the cutting can beperformed using the cutting assistance portion 60. In addition, in astate where the external force is not applied to the switching portion30, the switching portion 30 functions as the protector, and the cuttingassistance portion 60 can be prevented from inadvertently coming intocontact with the biological tissue. Accordingly, the safety when in useis further improved. For example, even in a case where the cuttingassistance portion 60 includes the blade surface having the relativelystrong cutting force and the saw-tooth shape, non-corrugated blade, thesafety when in use can be maintained extremely high. Therefore, thestructure or the shape of the cutting assistance portion 60 can be morefreely designed in a wider range, and various functions can be providedfor the cutting assistance portion 60.

In a state where the external force is not applied to the switchingportion 30, for example, the distal end of the cutting assistanceportion 60 may be disposed on the distal side beyond the distal end ofthe cutting edge 21, or may be disposed at a position which is the sameas that of the distal end of the cutting edge 21.

Next, a medical device according to Modification Example 6 of the firstexemplary embodiment will be described.

As illustrated in FIG. 11, in this modification example, a chamferedportion 161 a subjected to chamfering in an R-shape is disposed in adistal end 161 of the cutting assistance portion 160. The R-shape is anatraumatic configuration defining a dome configuration. The chamferedportion 161 a is disposed in the cutting assistance portion 160.Accordingly, when the cutting is performed by rotating the rotary body20, an orbit r2 drawn by the cutting assistance portion 160 forms aconvex shape (dome shape) curved from the distal side toward theproximal side. Even if the cutting assistance portion 60 comes intocontact with the vascular wall during the treatment, it is possible toprevent a force from being applied to and scratching the vascular wall.Accordingly, the safety when in use can be further improved.

A curvature of the chamfered portion 161 a is not particularly limited,and can be appropriately changed.

Next, a medical device 100 according to Modification Example 7 of thefirst exemplary embodiment will be described.

In this modification example, a configuration of each portion of themedical device 100 is modified so that the treatment using a guide wireW can be more smoothly performed. In the medical device 1 describedabove, an example has been described in which the drive shaft 10 is usedas the elongated member for transmitting the rotational force to therotary body 20. In the medical device 100 according to this modificationexample, a coil 90 is used as the elongated member for transmitting therotational force to the rotary body 20. FIG. 12 is a plan viewillustrating an overall configuration of the medical device 100according to this modification example. FIG. 13A is an enlargedcross-sectional view illustrating the periphery of the proximal portion.FIG. 13B is an enlarged cross-sectional view illustrating the peripheryof the distal portion.

As illustrated in FIG. 13B, the coil 90 is inserted into the lumen 85 ofthe tube 80. The rotary body 20 is attached to the distal end of thecoil 90. In addition, the rotation receiving portion 50 is attached tothe distal end of the tube 80.

As illustrated in FIG. 13A, a relay tube 95 is attached to the proximalend of the tube 80. The proximal end of the coil 90 is attached to theinner surface of the distal end of the relay tube 95.

As illustrated in FIG. 13A, the hub 151 is attached so as to surroundthe outer periphery of the relay tube 95. As illustrated in FIG. 12, theproximal portion of the relay tube 95 is pulled out from the hub 151 bybeing inserted into the proximal end port 152 of the hub 151. Inaddition, the relay tube 95 is inserted into the valve body 157 disposedinside the hub 151.

As illustrated in FIG. 13A, an opening portion 96 is disposed in therelay tube 95. A lumen 95 a of the relay tube 95 communicates with theinterior of the connector portion 153 disposed in the hub 151 via theopening portion 96. The debris D generated during the treatment usingthe medical device 100 can be discharged outward of the relay tube 95through the lumen 95 a and the opening portion 96 of the relay tube 95.

As illustrated in FIG. 13B, the coil 90 is surrounded by the tube 80.The tube 80 prevents the aspirated fluid and the debris D from leakingout through a gap of the coil 90. For example, the tube 80 can beconfigured to include a resin-made single layer tube formed of a knownresin material.

The relay tube 95 is configured to be rotatable by the rotational driveforce transmitted from the external drive apparatus 180. As illustratedin FIG. 12, the external drive apparatus 180 is provided with a secondmovement mechanism 186 a which applies the rotational drive force to therelay tube 95 in cooperation with a first movement mechanism 86 adisposed in the relay tube 95. For example, the first movement mechanism86 a can be configured to include a driven gear. For example, the secondmovement mechanism 186 a can be configured to include a driving gearmeshing with the driven gear. For example, the external drive apparatus180 includes a known drive unit such as an electric motor including thedrive shaft.

If a power source is turned on for the external drive apparatus 180 andthe drive shaft is rotated by supplying a drive current, the drivinggear (second movement mechanism) 186 a is rotated, and the driven gear(first movement mechanism) 86 a is rotated in response to the rotationof the driving gear 186 a. If the driven gear 86 a is rotated, the relaytube 95 is rotated in response to the rotation (an arrow r11 in FIG. 13Aindicates the rotation). If the relay tube 95 is rotated, the coil 90attached to the relay tube 95 is rotated (an arrow r13 in FIGS. 13A and13B indicates the rotation). Then, if the coil 90 is rotated, the rotarybody 20 disposed in the distal end of the coil 90 is rotated (an arrowr12 in FIG. 13B indicates the rotation).

As illustrated in FIG. 13A, a valve body 158 is disposed in the proximalend of the relay tube 95. The valve body 158 is provided with aninsertion hole 159 into which the guide wire W is inserted. The guidewire W is inserted into the lumen 95 a of the relay tube 95 by insertingthe valve body 158. In addition, as illustrated in FIG. 136, the guidewire W is inserted into the lumen 95 a of the relay tube 95, and thedistal portion is guided into the lumen 90 a of the coil 90 disposed inthe distal end of the relay tube 95, the rotary body 20, and theswitching portion 30. The guide wire W is pulled out from the distalopening portion of the switching portion 30, and the distal portion isguided to the distal side of the rotary body 20. The guide wire W can beeasily inserted from the proximal end to the distal end of the relaytube 95. Accordingly, when the treatment is performed using the medicaldevice 100, the guide wire W can be smoothly operated.

In this modification example, in order to smoothly and easily insert theguide wire W into the rotary body 20 and the switching portion 30, thecutting assistance portion 60 is not disposed in the rotary body 20.

A material or a structure of the coil 90 and the relay tube 95 is notparticularly limited, as long as both of these can be configured so thatthe rotary body 20 can be rotated in conjunction with the rotation. Inaddition, a fixing method or a fixing position between the coil 90 andthe tube 80, a fixing method or a fixing position between the relay tube95 and the tube 80, and a fixing method or a fixing position between thecoil 90 and the relay tube 95 are not particularly limited, as long asthe rotational drive force can be transmitted to the rotary body 20.

In the above-described exemplary first embodiment and the respectivemodification examples, the tubular rotary body having the cutting edgeformed on the distal surface has been described as an example. However,a configuration of the rotary body is not particularly limited, as longas the cutting can be performed using the cutting edge. For example, thecutting edge may be formed on the side surface of the rotary bodyinstead of the front surface of the rotary body. In addition, a shape ora material of additional members such as the rotation receiving portionand the cutting assistance portion can be appropriately modified inaccordance with product specifications of the medical device, and theshape or the material is not limited to the above-describedconfiguration.

Second Embodiment

Next, a medical device 2 according to a second exemplary embodiment willbe described. In describing the second embodiment, description will beappropriately omitted with regard to members which can be configuredsimilar to the medical device 1 and the medical device 100 according tothe first exemplary embodiment described above. In addition, structureswhich are not specifically described in the second exemplary embodimentcan be configured similar to the first embodiment.

Referring to FIG. 14, the medical device 2 according to the secondexemplary embodiment is different from the above-described medicaldevice 1 in a structure on the distal side of the tube 80. Specifically,the medical device 2 has a distal member 400 for adjusting a contactposition where the rotary body 20 is brought into contact with thestenosed site S when the rotary body 20 is used so as to treat thestenosed site S (refer to FIG. 18B).

As illustrated in FIG. 14, in brief, the medical device 2 has therotatable drive shaft 10, the rotary body 20 including the cutting edge21 and rotated in conjunction with the rotation of the drive shaft 10,the protector (switching portion) 30, the cutting assistance portion 60,and the distal member 400 disposed in the rotary body 20.

As illustrated in FIGS. 15A and 15B, the distal member 400 has a hollowmain body portion 410 including a lumen 415 and a side hole 416 open onthe side surface, and a support portion 420 that extends to the distalside beyond the distal end of the rotary body 20, and that is configuredto be capable of supporting the rotary body 20 with respect to thebiological lumen such as the blood vessel H.

The rotary body 20 can be inserted into and disposed in the main bodyportion 410 of the distal member 400. The main body portion 410 holdsthe rotary body 20 in the lumen 415. The main body portion 410 isprovided with a function to serve as the rotation receiving portionwhich prevents the rotary shaft of the rotary body 20 from beingdeviated, when the rotary body 20 is rotated. As illustrated in FIG.16A, the distal member 400 is mounted on the outer surface of the rotarybody 20.

The support portion 420 of the distal member 400 is disposed so as toextend to the distal side beyond the distal end of the rotary body 20 ina state where the rotary body 20 is inserted into the main body portion410 (refer to FIG. 14). The support portion 420 is configured so thatthe distance from the rotary body 20 is variable in a first direction(the direction of an arrow a-a′ in FIG. 15A) which intersects theextending direction of the rotary body 20.

In the second exemplary embodiment, the first direction is set to avertical direction (also referred to as a “height direction”) orthogonalto the extending direction (axial direction) of the distal member 400.However, the first direction is not particularly limited, as long as thefirst direction is a direction in which the rotary body 20 is movedclose to the stenosed site S serving as the cutting target in themedical procedure using the medical device 2. The first direction is notlimited to only the vertical direction.

The support portion 420 has an elastically deformable first site 421that extends gradually away from the rotary body 20 in the firstdirection, and a second site 422 that extends to the distal side beyondthe first site 421 and that has a guide wire insertion portion (lumen)423 into which the guide wire W can be inserted.

In a state where the external force is not applied, the first site 421of the support portion 420 has a shape protruding outward beyond therotary body 20 in a second direction (direction of an arrow b-b′ in FIG.15B) intersecting each of the first direction and the extendingdirection of the rotary body 20.

In the second exemplary embodiment, the second direction is set to ahorizontal direction (also referred to as a “width direction”)orthogonal to the first direction. However, the second direction is notparticularly limited, as long as the rotary body 20 can align with apredetermined position in the medical procedure using the medical device2. For example, the second direction can be appropriately changed inconjunction with the change in the first direction.

As illustrated in FIG. 15B, the first site 421 has a shape spreading ina direction symmetrical to a rotary shaft R1 of the rotary body 20. Inaddition, the first site 421 is configured to include a first armportion 421 a and a second arm portion 421 b.

The first arm portion 421 a and the second arm portion 421 b have asubstantially symmetrical shape with reference to the rotary shaft R1.The proximal end of the first arm portion 421 a and the proximal end ofthe second arm portion 421 b are connected to the main body portion 410,and the distal end of the first arm portion 421 a and the distal end ofthe second arm portion 421 b are connected to the second site 422. Anannular space is defined between the respective arm portions 421 a and421 b. As illustrated in FIG. 15A, the respective arm portions 421 a and421 b have a convex shape which is gently curved from the main bodyportion 410 toward the distal side along the first direction. The distalside connected to the second site 422 is farthest away from the mainbody portion 410.

As illustrated in FIGS. 15A and 15B, the distal member 400 further hasan auxiliary support portion 460 that extends to the proximal sidebeyond the proximal end of the rotary body 20 and that is configured tobe capable of supporting the rotary body 20 with respect to the bloodvessel H. The auxiliary support portion 460 has a shape substantiallysymmetrical to the support portion 420 with reference to the centerposition of the main body portion 410. Similar to the support portion420, the auxiliary support portion 460 is configured so that thedistance from the rotary body 20 is variable in the first direction(direction of the arrow a-a′ in FIG. 15A) which intersects the extendingdirection of the rotary body 20.

The auxiliary support portion 460 has an elastically deformable firstauxiliary site 461 that extends gradually away from the rotary body 20in the first direction, and a second auxiliary site 462 that extends tothe proximal side beyond the first auxiliary site 461 and that has aguide wire insertion portion (lumen) 463 into which a guide wire W canbe inserted.

In a state where the external force is not applied, the first auxiliarysite 461 of the auxiliary support portion 460 has a shape protrudingoutward beyond the rotary body 20 in the second direction (direction ofthe arrow b-b′ in FIG. 15B).

The first auxiliary site 461 has a shape spreading in the directionsymmetrical to the rotary shaft R1 of the rotary body 20. The firstauxiliary site 461 is configured to include a first arm portion 461 aand a second arm portion 461 b. The first arm portion 461 a and thesecond arm portion 461 b are configured to have substantially the sameshape as the respective arm portions 421 a and 421 b included in thesupport portion 420. Accordingly, description of the shape will beomitted.

The main body portion 410, the support portion 420, and the auxiliarysupport portion 460 of the distal member 400 can be integrallyconfigured to include a known metal material or resin material, forexample. In the second exemplary embodiment, the above-described membersare integrally configured to include metal provided withbiocompatibility. In addition, each outer surface of the main bodyportion 410, the support portion 420, and the auxiliary support portion460 is coated with a resin-made coating member (for example, a knownheat-shrinkable tube). The above-described members can be integrallyinterlocked with each other by thermally shrinking the coating member.

The first site 421 of the support portion 420 and the first auxiliarysite 461 of the auxiliary support portion 460 can be configured toinclude a flat plate-shaped member, for example. In addition, the secondsite 422 of the support portion 420 and the second auxiliary site 462 ofthe auxiliary support portion 460 can be configured to internallyinclude a hollow tubular member, for example.

As illustrated in FIG. 16A, the distal member 400 is mounted on theouter surface of the rotary body 20, when the treatment is performedusing the medical device 2. The support portion 420 (first site 421) andthe auxiliary support portion 460 (first auxiliary site 461) of thedistal member 400 generate tension for raising the rotary body 20 upward(in a direction of an arrow a in the drawing). A position for mountingthe distal member 400 on the rotary body 20 can be appropriately set toa position at which the cutting edge 21 of the rotary body 20 is notcovered by the distal end of the distal member 400. A distance (height)for raising the rotary body 20 can be set within 7 mm, for example, in acase where the medical device 2 is applied to the treatment for theblood vessel H.

In addition, the distal member 400 is externally mounted on the rotarybody 20. Accordingly, the support portion 420 or the auxiliary supportportion 460 included in the distal member 400 does not need to beaccommodated in or inserted into the rotary body 20. Therefore, therotary body 20 itself can be avoided from increasing in diameter.Accordingly, it is possible to prevent the rotary body 20 from beingunsatisfactorily delivered into the blood vessel H due to the increaseddiameter of the rotary body 20, and it is possible to prevent the rotarybody 20 from being unsatisfactorily inserted into the stenosed site S.

As illustrated in FIG. 16B, a curved shape is added to the distalportion 88 a of the tube 80. The curved shape is added so as to preventan orientation of the distal surface of the rotary body 20 from beinginclined upward or downward. For example, when the treatment isperformed using the rotary body 20, if the guide wire W is inserted intothe second site 422 and the second auxiliary site 462, due to theelasticity of the guide wire W, the first site 421 of the supportportion 420 and the first auxiliary site 461 of the auxiliary supportportion 460 may be curved so as to follow the curve of the guide wire W,in some cases. If these are curved in this way, the orientation of thedistal surface of the rotary body 20 which is indicated by an arrow e isinclined upward or downward, thereby causing a possibility that theorientation of the cutting edge 21 may be directed in an unintendeddirection. As illustrated, a predetermined curved shape is added to thedistal portion 88 a of the tube 80 so as to be capable of maintaining astate where the orientation of the rotary body 20 faces the frontsurface. In this manner, it is possible to adjust the orientation of therotary body 20 so as to face the front surface side when the cutting isperformed.

When the treatment is performed using the rotary body 20, a stateillustrated in FIG. 17A is switched to a state illustrated in FIG. 17Bin accordance with the rotation of the rotary body 20. The stateillustrated in FIG. 17A means a state where the debris D is preventedfrom flowing from the side surface of the rotary body 20, and the stateillustrated in FIG. 17B means a state where the debris D can flow fromthe side surface of the rotary body 20. Since the rotary body 20 isrotated, if the side hole 23 disposed on the side surface of the rotarybody 20 and the side hole 416 disposed on the side surface of the distalmember 400 are disposed so as to overlap each other, the inner side andthe outer side of the rotary body 20 are brought into a communicatingstate. Accordingly, the debris D flows into the rotary body 20 and intothe holding portion 40 (stretchable and deformable portion 35) via theside hole 23. The debris D flows into the tube 80, and is collected onthe proximal side of the tube 80. The debris D can be collected via theside hole 23. Accordingly, similar to the above-described embodiment, itis possible to improve efficiency in collecting the debris D.

Next, a treatment method using the medical device 2 will be describedwith reference to FIGS. 18A to 18C. Herein, a method of cutting thestenosed site S formed in the blood vessel H will be described as anexample.

First, as illustrated in FIG. 18A, the guiding sheath 170 is introducedto the vicinity of the stenosed site S. The guiding sheath 170 can bedelivered to the vicinity of the stenosed site S along the previouslyintroduced guide wire W.

Next, the medical device 2 is delivered to the vicinity of the stenosedsite S along with the guide wire W. In this case, the guide wire W isinserted into the second site 422 of the support portion 420 and thesecond auxiliary site 462 of the auxiliary support portion 460. In thismanner, the distal member 400 can be smoothly moved to a predeterminedposition. In a state where the distal member 400 is accommodated insidethe guiding sheath 170, the distal member 400 is pushed against theinner wall of the guiding sheath 170, and is shrunk in the heightdirection (direction of the arrow a′ in FIG. 15) and the width direction(direction of the arrow b′ in FIG. 15).

As illustrated in FIG. 18B, if the distal member 400 protrudes outwardof the guiding sheath 170 via the distal opening portion of the guidingsheath 170, the first site 421 of the support portion 420 is deformed soas to spread in the height direction and the width direction, until thefirst site 421 of the support portion 420 is attached to the inner wallof the blood vessel H. Similarly, the first auxiliary site 461 of theauxiliary support portion 460 is deformed so as to spread in the heightdirection and the width direction, until the first auxiliary site 461 ofthe auxiliary support portion 460 is attached to the inner wall of theblood vessel H.

The rotary body 20 having the distal member 400 attached thereto israised in the height direction. In this manner, the rotary body 20 isdisposed at a position facing the stenosed site S formed on the innerwall of the blood vessel H. In addition, the first site 421 and thefirst auxiliary site 461 which spread in the width direction cause therotary body 20 to be disposed at a position where the rotary shaft R1overlaps the respective guide wire insertion portions 423 and 463 (referto FIG. 15B). In this manner, the rotary shaft R1 passing through thecenter of the distal member 400 is disposed substantially parallel tothe delivery of the guide wire W. If the rotary body 20 is moved towardthe stenosed site S in this state, the rotary body 20 moves parallel tothe delivery of the guide wire W, and is pushed against the stenosedsite S, in a state where the cutting edge 21 located in the distal endof the rotary body 20 faces the stenosed site S.

As described above, the rotary body 20 comes into contact with thestenosed site S serving as the cutting target after the position isappropriately adjusted in the height direction and the width direction(the height direction and the width direction on the axially orthogonalcross-section) of the blood vessel H. Accordingly, the cutting forcegenerated by the cutting edge 21 can satisfactorily act on the stenosedsite S, and the stenosed site S can be efficiently cut.

In addition, the first site 421 of the support portion 420 and the firstauxiliary site 461 of the auxiliary support portion 460 are elasticallydeformed in response to the inner diameter of the blood vessel H.Accordingly, in a state where the external force is not applied, even ina case where the blood vessel H having a smaller inner diameterdimension than the first site 421 and the first auxiliary site 461 isthe treatment target, the diameter of the whole distal member 400 isreduced, and the distal member 400 is moved inside the blood vessel H.Therefore, the medical device 2 can be satisfactorily delivered into theliving body.

Next, as illustrated in FIG. 18C, the medical device 2 is moved to thedistal side so that the cutting edge 21 of the rotary body 20 is pushedagainst the stenosed site S, thereby cutting the stenosed site S. Whenthe cutting edge 21 is rotated so as to cut off the stenosed substanceof the stenosed site S, for example, the aspiration device 190 can beoperated so as to aspirate the scraped debris D into the rotary body 20.

After the cutting treatment is completely performed on the stenosed siteS, the medical device 2 is appropriately removed outward of the livingbody. It is also possible to subsequently perform the cutting treatmenton the other stenosed site S.

As described above, the medical device 2 according to the secondexemplary embodiment has the rotatable drive shaft 10, the rotary body20 that includes the cutting edge 21 for applying the cutting force tothe stenosed site S, and that is disposed on the distal side of thedrive shaft 10 so as to be rotated in conjunction with the rotation ofthe drive shaft 10, and the distal member 400 disposed in the rotarybody 20. The distal member 400 has the support portion 420 that extendsto the distal side beyond the distal end of the rotary body 20, and thatis configured to be capable of supporting the rotary body 20 withrespect to the blood vessel H. The support portion 420 is configured sothat the distance from the rotary body 20 is variable in the firstdirection (height direction) in which the rotary body 20 is moved closeto the stenosed site S.

According to the medical device 2 configured as described above, therotary body 20 is supported by the support portion 420 so as to alignwith the stenosed site S inside the blood vessel H. In a state where therotary body 20 aligns with the stenosed site S, the cutting edge 21comes into contact with the stenosed site S. Accordingly, the cuttingforce can be satisfactorily applied to the stenosed site S. In thismanner, the stenosed site S can be efficiently cut, and further, thecutting edge 21 can be preferably prevented from coming into contactwith the biological tissue other than the stenosed site S.

In addition, the support portion 420 has the elastically deformablefirst site 421 that extends gradually away from the rotary body 20 inthe first direction, and the second site 422 that extends to the distalside beyond the first site 421, and that includes the guide wireinsertion portion 423 into which the guide wire W can be inserted.Therefore, since the elastic deformation of the first site 421 is used,the rotary body 20 can easily align with the stenosed site S.Furthermore, the guide wire W is inserted into the guide wire insertionportion 423. In this manner, the distal member 400 of the medical device2 can be delivered to a predetermined position inside the living body.Accordingly, excellent operability is achieved.

In a state where the external force is not applied, the first site 421has a shape protruding outward beyond the rotary body 20 in the seconddirection which intersects each of the first direction and the extendingdirection of the rotary body 20. Therefore, the first site 421 is likelyto be attached to the inner wall of the blood vessel H. This attachmentallows the distal member 400 to be supported on the inner wall of theblood vessel H. The distal member 400 is supported on the inner wall ofthe blood vessel H. Accordingly, it is possible to prevent the rotaryshaft of the rotary body 20 from being deviated when the stenosed site Sis cut. Therefore, the stenosed site S can be efficiently cut.

In addition, the first site 421 has the shape spreading in the directionsymmetrical to the rotary shaft R1 of the rotary body 20. Accordingly,the center position of the distal member 400 can align with the rotaryshaft R1 of the rotary body 20. Furthermore, the center position of thedistal member 400 can align with the center position in the widthdirection of the blood vessel H. Therefore, the stenosed site S can bemore efficiently cut.

The distal member 400 further has the auxiliary support portion 460 thatextends to the proximal side beyond the proximal end of the rotary body20, and that is configured to be capable of supporting the rotary body20 with respect to the blood vessel H. In this manner, the distal member400 can be raised on the distal side and the proximal side of the distalmember 400. Accordingly, the distal member 400 can be more reliablyraised, and it is possible to prevent a gap in the height direction frombeing generated between the distal side and the proximal side of thedistal member 400 when the distal member 400 is raised. Therefore, therotary body 20 can properly align with the stenosed site S.

The auxiliary support portion 460 has the elastically deformable firstauxiliary site 461 that extends gradually away from the rotary body 20in the first direction, and the second auxiliary site 462 that extendsto the proximal side beyond the first auxiliary site 461, and thatincludes the guide wire insertion portion 463 into which the guide wireW can be inserted. Therefore, the rotary body 20 can be raised to aproper position by the first site 421 of the support portion 420 and thefirst auxiliary site 461 of the auxiliary support portion 460. Moreover,the distal member 400 can be smoothly moved to a predetermined positionby the guide wire W inserted into the second site 422 of the supportportion 420 and the second auxiliary site 462 of the auxiliary supportportion 460.

The treatment method according to the second exemplary embodiment hasthe cutting step of bringing the rotary body 20 including the cuttingedge 21 for applying the cutting force to the stenosed site S inside theblood vessel H into a supported state in the first direction (heightdirection) in which the rotary body 20 is moved close to the stenosedsite S, and performing the cutting by bringing the cutting edge 21 intocontact with the stenosed site S while rotating the rotary body 20.

According to the treatment method having the above-described step, therotary body 20 is supported, and the position of the rotary body 20 isadjusted with respect to the stenosed site S inside the blood vessel H.Thereafter, the stenosed site S is cut by the rotary body 20. In thismanner, the cutting force can satisfactorily act on the stenosed site S.Furthermore, the cutting edge 21 can be preferably prevented from cominginto contact with the biological tissue other than the stenosed site S.

In addition, the cutting step can be performed in a state where therotary body 20 is supported in the second direction (width direction)which intersects each of the first direction and the extending directionof the rotary body 20. Accordingly, the distal member 400 can besupported inside the blood vessel H in a more stable state. The rotaryshaft of the rotary body 20 can be prevented from being deviated whenthe stenosed site S is cut. In this manner, the stenosed site S can beefficiently cut.

In addition, the cutting step can be performed in a state where therotary body 20 is supported by the support portion 420 extending to thedistal side of the rotary body 20 and the auxiliary support portion 460extending to the proximal side of the rotary body 20. In this manner,the distal member 400 can be more reliably raised, and it is possible toprevent a gap in the height direction from being generated between thedistal side and the proximal side of the distal member 400 when thedistal member 400 is raised. Therefore, the rotary body 20 can properlyalign with the stenosed site S.

The treatment method also may have the aspirating step of aspirating thecut debris D into the rotary body 20. Accordingly, the debris D can bequickly discharged outward of the blood vessel H, and the treatment timecan be shortened.

Next, a medical device according to Modification Example 1 of the secondexemplary embodiment will be described.

As illustrated in FIGS. 19A and 19B, a distal member 510 according toModification Example 1 includes a link structure 512 for maintaining anorientation of the distal surface of the rotary body 20 indicated by anarrow e to be a predetermined direction. For example, the link structure512 can be configured to include a slit disposed in a main body portion511 of the distal member 510. The link structure 512 provides the distalmember 510 with an added shape in which the central portion on the lowersurface side of the distal member 510 is warped to the upper surfaceside. The warpage of the distal member 510 prevents the distal surfaceof the rotary body 20 inserted into the main body portion 511 fromfacing a lower side (lower side in FIG. 18A, which is the side away fromthe stenosed site S) from the position parallel to the running of theblood vessel H. In this manner, the cutting edge 21 can be preventedfrom coming into contact with the biological tissue other than thestenosed site S.

In this modification example, the guide wire insertion portion 423 isconfigured to include a through-hole disposed in the distal end of thesupport portion 420, and the guide wire insertion portion 463 isconfigured to include a through-hole disposed in the proximal end of theauxiliary support portion 460. Even in a case where the guide wireinsertion portions 423 and 463 are configured to include thethrough-holes disposed in the respective support portions 420 and 460,the rotary body 20 can be smoothly delivered or moved using the guidewire W. In addition, the distal member 510 can be miniaturized comparedto a case of using the hollow member such as the second site 422 and thesecond auxiliary site 462 which are illustrated in the above-describedembodiment. Furthermore, it is possible to reduce the manufacturing costby reducing the number of components.

Next, a medical device according to Modification Example 2 of the secondexemplary embodiment will be described.

As illustrated in FIGS. 20A and 20B, a distal member 520 according toModification Example 2 has an elastically deformable connection portion550 connected to the support portion 420 and the auxiliary supportportion 460.

In a state where the external force is not applied, the connectionportion 550 has a shape protruding outward (upward-downward direction inFIG. 20B) from the support portion 420 and the auxiliary support portion460 in the direction intersecting the extending direction of the rotarybody 20.

In the connection portion 550, a distal portion 551 connected to thesupport portion 420 and a proximal portion 552 connected to theauxiliary support portion 460 respectively have shapes spreading inmutually symmetrical directions with respect to the rotary shaft R1 ofthe rotary body 20. In this modification example, the connection portion550 has an S-shape in a plan view. However, the embodiment is notlimited thereto. For example, the connection portion 550 may have ashape of a FIG. 8 in a plan view.

For example, the connection portion 550 can be configured to include anelastically deformable metal wire rod or a resin-made wire rod.

FIG. 20C schematically illustrates an axially orthogonal cross-sectionof the blood vessel H. For example, the illustrated blood vessel H is aflattened blood vessel H having a long dimension of the lumen in theupward-downward direction and a short dimension of the lumen in therightward-leftward direction. If the distal member 520 is introducedinto the blood vessel H, the connection portion 550 spreads in a minoraxis direction (rightward-leftward direction in the drawing) of theblood vessel H. In this manner, the central position of the distalmember 520, that is, the rotational center of the rotary body 20 isallowed to align with the central position of the blood vessel H in theminor axis direction. Therefore, it is possible to preferably preventthe cutting edge 21 of the rotary body 20 from coming into contact withthe biological tissue other than the stenosed site S. The connectionportion 550 is attached to the inner wall of the blood vessel H so as toincrease a supporting force of the distal member 520 for supporting theblood vessel H. Accordingly, it is possible to prevent the orientationof the cutting edge 21 from being displaced while the cutting treatmentis performed.

When the connection portion 550 is inserted into the guiding sheathwhose inner diameter is smaller than the width (length in theupward-downward direction in FIG. 20B) of the connection portion 550 inan expanded state, the connection portion 550 is elastically deformedinto a substantially linear shape as illustrated by a two-dot chain linein FIG. 20B. Accordingly, the width decreases. Therefore, the distalmember 520 can also be smoothly moved inside the guiding sheath having arelatively small diameter.

Next, a medical device according to Modification Example 3 of the secondexemplary embodiment will be described.

As illustrated in FIGS. 21A and 21B, in a distal member 530 according toModification Example 3, the support portion 420 includes a third site430 that extends between the first site 421 and the second site 422. Thethird site 430 is configured to include a member which is more flexiblethan the second site 422.

For example, the third site 430 can be configured to include ametal-made hollow member which has a slit and which can be curved. Forexample, the second site 422 can be configured to include a resin-madehollow member which is more rigid (harder) than the third site.

The third site 430 is connected to the second site 422 via apredetermined relay member 433. For example, the relay member 433 can beconfigured to include a resin-made coating member (for example, a knownheat-shrinkable tube) which integrally interlocks the second site 422and the third site 430 with each other. For example, the first site 421and the third site 430 are appropriately connected to each other usingan adhesive.

FIG. 21B illustrates a treatment example when using the distal member530 according to Modification Example 3 in the blood vessel H where abranched blood vessel H1 is present on the distally located side (distalside) of the stenosed site S.

For example, if the guide wire W is introduced into the branched bloodvessel H1 present on the distally located side of the stenosed site Sand is greatly curved toward the branched blood vessel H1 side, thedistal member 530 is affected by the curve of the guide wire W.Accordingly, an orientation, a posture, or a position of the distalmember 530 may be corrected in the curved direction, in some cases. Inaddition, if the orientation of the distal member 530 is corrected,there is a possibility that the cutting edge 21 may be pushed againstthe vascular wall on the side having the stenosed site S by a forcestronger than expected. In contrast, according to the distal member 530of this modification example, the third site 430 located on the proximalside of the second site 422 is more flexible than the second site 422.Accordingly, since the second site 422 is curved, it is possible torestrain the rotary body 20 from being affected by the delivery thecurved guide wire W. Therefore, when the guide wire W is used so as todeliver the rotary body 20 to a desired site, even if the guide wire Wis greatly curved on the distal side, it is possible to prevent thecutting edge 21 from being directed in an unintended direction afterbeing affected by the curve, or from being pushed against the vascularwall by the pushing force stronger than expected.

Next, a medical device according to Modification Example 4 of the secondexemplary embodiment will be described.

Referring to FIG. 22, in this modification example, a shape memorymember is used for the tube 80 connected to the proximal side of adistal member 400. The tube 80 is configured to raise the distal member400 by being restored to a pre-memorized shape. The tube 80 is providedin advance with a curved shape which raises the distal member 400 in theheight direction (upward direction in the drawing) when the tube 80 ispulled out from the guiding sheath used in the medical procedure.

For example, the tube 80 can be configured to include a hollow elongatedshape memory member 80 a, a heat-shrinkable tube (not illustrated)disposed to coat an outer surface thereof, and a hollow member 80 bconnected to the proximal side of the shape memory member 80 a. In thismodification example, heat is applied to the heat-shrinkable tubedisposed so as to cover the shape memory member 80 a. In this manner,the heat-shrinkable tube is integrally attached to the shape memorymember 80 a. For example, the hollow member 80 b connected to theproximal side of the tube 80 can be configured to include a hollow metaltube.

For example, as the shape memory member 80 a, a known shape memory alloycan be used. For example, as the shape memory alloy can be, a titaniumalloy (Ti—Ni, Ti—Pd, and Ti—Nb—Sn) or a copper alloy can be used. Inaddition, for example, as the shape memory member 80 a, a known shapememory resin (shape memory polymer) can be used. For example, as theshape memory resin, acrylic resin, toluene copolymer, polynorbornene,styrene-butadiene copolymer, and polyurethane can be used.

In the medical procedure using the medical device 2 including a raisingmechanism (support portion 420) extending from the distal member 400 tothe distal side, even in a case where the treatment is performed in astate where the orientation of the cutting edge 21 is inclined in thedownward direction (for example, an inclination angle 9 is 90° orsmaller) as illustrated in FIG. 23, the cutting edge 21 and the lowersurface of the vascular wall are separated from each other by thesupport portion 420. Therefore, it is possible to prevent the cuttingedge 21 from inadvertently coming into contact with the vascular wall.Accordingly, the treatment can be performed on the stenosed site S whilethe vascular wall is more preferably prevented from being damaged.

Next, a medical device according to Modification Example 5 of the secondexemplary embodiment will be described.

As illustrated in FIGS. 24A and 24B, a distal member 530 illustrated inthis modification example has a main body portion 531 into which therotary body 120 including the cutting edge 121 is inserted, side surfaceportions 532 a and 532 b extending from the main body portion 531 towardthe distal side, a bottom surface portion 533 disposed on the bottomsurface side of the cutting edge 121, and a support portion 535 whichsupports the rotary body 120 on the distal side.

A gap between the side surface portion 532 a and the side surfaceportion 532 b gradually decreases toward the distal side. In addition,the distal side of the respective side surface portions 532 a and 532 bis inclined toward the bottom surface portion 533 side. An openingportion 532 c is disposed on the side surface of the respective sidesurface portions 532 a and 532 b.

The rotary body 120 is disposed in a state of being interposed betweenthe respective side surface portions 532 a and 532 b. Accordingly, therotary body does not inadvertently protrude therefrom. Even in a casewhere the rotary body 120 is damaged, the rotary body 120 is held by therespective side surface portions 532 a and 532 b and the bottom surfaceportion 533. Therefore, the rotary body 120 is prevented from falling.Furthermore, the respective side surface portions 532 a and 532 bprevent the rotary body 120 from inadvertently protruding on the distalside of the rotary body 120, thereby preventing the rotary body 120 fromexcessively entering the stenosed site S. In this manner, it is possibleto preferably prevent the normal tissue from being damaged by thecutting edge 121. In addition, the cutting edge 121 applies the cuttingforce to the stenosed site S from the side surface of the main bodyportion 531 via the opening portion 532 c. Therefore, the stenosed siteS can be efficiently cut.

On the distal side beyond the cutting edge 121 of the rotary body 120, aguide surface A1 is formed by the distal surface of the respective sidesurface portions 532 a and 532 b. The guide surface A1 supports therotary body 120 with respect to the stenosed site S while the treatmentis performed by bringing the cutting edge 121 into contact with thestenosed site S, thereby preventing the cutting edge 121 and the rotarybody 120 from being separated from the stenosed site S. In this manner,the cutting edge 121 is prevented from moving outward of the biologicallumen (for example, in a direction toward the lower surface of the bloodvessel H which is illustrated in FIG. 20C). In addition, the guidesurface A1 limits a range in the height direction where the cutting edge121 applies the cutting force to a range of a portion where the cuttingedge 121 is exposed from the respective side surface portions 532 a and532 b (range of a height h illustrated in FIG. 24B). Therefore, even ina case where the cutting is performed after the cutting edge 121inadvertently comes into contact with a site other than the stenosedsite S, and in a case where the tube wall of the biological lumen isthicker than the height h, it is possible to sufficiently suppress adisadvantage that the biological lumen may be perforated.

For example, as illustrated, the support portion 535 can be configuredto include a single member whose width gradually decreases toward thedistal side and whose distal side is curved downward. Although notillustrated, the second site 422 (refer to FIGS. 15A and 15B) having theguide wire insertion portion (lumen) 423 can be appropriately attachedto the support portion 535. For example, the second site 422 can bedisposed on the distal side of the guide surface A1. In a case where thesecond site 422 is provided, the support portion 535 and the second site422 are coated with a resin-made coating member (for example, a knownheat-shrinkable tube) 539 as illustrated in FIG. 24B, and the coatingmember 539 can be thermally shrunk so that all of these are integrallyinterlocked with each other. For example, as the coating member 539, itis possible to use a hollow member configured to include fluorocarbonresin such as ethylene tetrafluoro ethylene copolymer (ETFE) andpolytetrafluoroethylene (PTFE), polyolefin such as polyethylene (PE) andpolypropylene (PP), polyamide, polyester, or polyurethane.

As illustrated in the respective modification examples, a specificconfiguration of the support portion is not particularly limited, aslong as the support portion provided with the function to raise therotary body has a structure which supports the rotary body inside thelumen of the blood vessel, and in which the distance from the rotarybody is variable. For example, as in Modification Example 6 illustratedin FIG. 25, the support portion 535 can be configured to include thefirst site 421 substantially linearly extending in the axial direction,and the second site 422 disposed in the distal portion of the first site421 and having the guide wire insertion portion 423. Even in a casewhere the first site 421 is substantially linearly disposed rather thana curved shape as in the support portion 535, if the second site 422comes into contact with the inner wall of the biological lumen, thefirst site 421 is supported on the inner wall of the biological lumen bythe contact. As a result, the rotary body 120 together with the firstsite 421 is raised, and the position of the rotary body 120 is adjustedin the height direction of the biological lumen. The first site 421 andthe second site 422 can be integrally interlocked with each other usinga resin-made coating member (for example, a known heat-shrinkable tube).

Hitherto, the medical device and the treatment method according to thedisclosure herein have been described with reference to the exemplaryembodiments and modifications thereto. However, the present invention isnot limited to only the contents described in the embodiments. Thepresent invention can be appropriately modified, based on the appendedclaims.

For example, each configuration described in the first exemplaryembodiment and the modification examples and each configurationdescribed in the second exemplary embodiment and the modificationexamples can be appropriately combined with each other, as long as thecombined configuration is not contradictory to the description in theappended claims, and the disclosure is not limited to the combinationsdescribed herein.

For example, the biological lumen serving as an application target ofthe medical device and the treatment method is not limited to the bloodvessel. For example, the disclosure may be applicable to a vessel, aureter, a bile duct, a fallopian tube, or a hepatic duct. In addition,the object serving as the cutting target is not limited to the stenosedsite.

The structure of each portion or the arrangement of the members in themedical device described in the exemplary embodiments can beappropriately modified. Using the additional members described withreference to the drawing can be appropriately omitted, and using otheradditional members can be appropriately omitted. Similarly, each steprelating to the treatment method or each device used for the treatmentcan be appropriately modified.

The detailed description above describes features, characteristics andoperational aspects of embodiments of a medical device and treatmentmethod representing examples of the medical device and treatment methoddisclosed herein. The disclosure and the present invention are notlimited, however, to the precise embodiments and variations described.Various changes, modifications and equivalents could be effected by oneskilled in the art without departing from the spirit and scope of thedisclosure as defined in the appended claims. It is expressly intendedthat all such changes, modifications and equivalents which fall withinthe scope of the claims are embraced by the claims.

What is claimed is:
 1. A medical device for cutting an object inside abiological lumen, comprising: a rotatable elongated member; a rotarybody that includes a cutting edge for applying a cutting force to theobject, and that is disposed on a distal side of the elongated member soas to be rotated in conjunction with rotation of the elongated member; aswitching portion whose distal end is disposed at a position protrudingfrom the cutting edge; and a holding portion configured to hold theswitching portion so as to move the switching portion on the same planeas the cutting edge or to a position away from the object beyond thecutting edge in accordance with a pushing force, when the switchingportion is pushed against the object.
 2. The medical device according toclaim 1, wherein a main body portion having a lumen for communicatingwith an interior of the rotary body is disposed in a proximal end of therotary body, and the holding portion is stretchable and deformable alongan extending direction of the main body portion.
 3. The medical deviceaccording to claim 2, wherein the main body portion has a tubular shapeincluding a distal opening portion, a proximal opening portion, and thelumen is linked to the distal opening portion and the proximal openingportion, at least a portion of the holding portion is inserted into themain body portion, and the switching portion is movable in aninward-outward direction of the main body portion by stretchabledeformation of the holding portion.
 4. The medical device according toclaim 2, wherein the holding portion is configured to include a hollowspring, and the switching portion is integrally disposed in a distalportion of the holding portion.
 5. The medical device according to claim4, further comprising a side hole through which an interior and anexterior of the holding portion communicate with each other, the sidehole being disposed on a side surface of the main body portion.
 6. Themedical device according to claim 1, further comprising: a cuttingassistance portion that is disposed in the rotary body, and thatprotrudes to a distal side beyond the cutting edge so as to assistcutting performed by the cutting edge.
 7. The medical device accordingto claim 6, wherein the cutting assistance portion has a substantiallyU-shape.
 8. The medical device according to claim 1, wherein the cuttingedge includes a tapered blade surface whose thickness is thinned towarda distal side of the rotary body.
 9. The medical device according toclaim 1, wherein the cutting edge includes a blade surface which is cutout in an uneven shape.
 10. The medical device according to claim 1,further comprising a cutting portion disposed in a distal end of theswitching portion, the cutting portion and the cutting edge of therotary body together applying the cutting force to the object.
 11. Themedical device according to claim 1, wherein the switching portion isdisposed on an outer surface of the rotary body.
 12. The medical deviceaccording to claim 2, further comprising a cutting portion disposed in adistal end of the switching portion, the cutting portion and the cuttingedge of the rotary body together applying the cutting force to theobject
 13. A treatment method for cutting an object inside a biologicallumen, comprising: moving a switching portion and bringing the switchingportion into a state of protruding to a distal side of a rotary bodyincluding a cutting edge for applying a cutting force to the object, andpushing the switching portion against the object so as to move theswitching portion on the same plane as the cutting edge or to a positionaway from the object beyond the cutting edge; and cutting the object bycausing the cutting edge to cut the object in a state where theswitching portion is moved.
 14. The treatment method according to claim13, wherein moving the switching portion is performed by causing aholding portion for holding the switching portion to be contracted anddeformed along an extending direction of a main body portion including alumen for communicating with an interior of the rotary body.
 15. Thetreatment method according to claim 14, wherein at least a portion ofthe holding portion is disposed inside the main body portion, and theswitching portion is movable in an inward-outward direction of the mainbody portion by stretchable deformation of the holding portion.
 16. Thetreatment method according to claim 14, wherein the holding portion is ahollow spring, and the switching portion is integrally disposed in adistal portion of the holding portion.
 17. The treatment methodaccording to claim 16, further comprising: introducing the cut objectinto the main body portion and into the holding portion via a side holedisposed on a side surface of the main body portion.
 18. The treatmentmethod according to claim 13, wherein the cutting step includes cuttingthe object while causing a cutting assistance portion disposed in therotary body to assist cutting performed by the cutting edge.
 19. Thetreatment method according to claim 13, further comprising: cutting theobject by using a blade surface disposed in a distal end of theswitching portion.